Aromasin

Introduction

Written by Sarah Lewis, PharmD
Medically reviewed by Dena Westphalen, PharmD
Updated on August 15, 2023

Exemestane (ex e MES tane) is a generic medication prescribed for certain breast cancers in people who’ve gone through menopause. Exemestane belongs to a group of drugs called aromatase inhibitors.

Side effects of exemestane

Exemestane may cause mild or serious side effects. More common mild side effects of exemestane and its serious side effects are listed below. This article doesn’t include all possible side effects of the drug. Side effects can vary based on your age, overall health, and any other medications you take.

To learn more about exemestane’s side effects, ask your doctor or pharmacist. You can also refer to the prescribing information for exemestane listed in the “Resources” section.

Mild side effects

More common mild side effects reported with exemestane are listed below.

This article doesn’t include all possible mild side effects of the drug. To learn more about exemestane’s side effects, refer to the prescribing information for exemestane listed in the “Resources” section.

With many drugs, mild side effects may go away within a few days or a couple of weeks. If the side effects are bothersome, tell your doctor or pharmacist. They may be able to suggest ways to manage them.

Exemestane oral tablet’s mild side effects include:

• fatigue (low energy)
• hot flashes
• joint pain
• headache
• mild allergic reaction*

* For details about this side effect, see the “Interactions and warnings for exemestane” section.

Serious side effects

Serious side effects of exemestane are listed below.

This article doesn’t include all possible serious side effects of the drug. To learn more about exemestane’s side effects, refer to the prescribing information for exemestane listed in the “Resources” section.

With many drugs, serious side effects are possible but not common. If you have serious side effects from this drug, call your doctor right away. If you’re having severe symptoms or a medical emergency, call 911 or a local emergency number.

In general, exemestane’s serious side effects include:

• depression
• hair loss
• heart problems, including heart attack and angina (chest pain)
• high blood pressure
• reduced bone density, which can increase the risk of fractures and osteoporosis
• severe allergic reaction*

* For details about this side effect, see the “Interactions and warnings for exemestane” section.

Common questions about exemestane

Below you’ll find answers to a few commonly asked questions about exemestane.

How does exemestane compare with letrozole and anastrozole?

Exemestane, letrozole, and anastrozole are all aromatase inhibitors (AIs). They’re prescribed for the same purpose and have similar side effects.

These three drugs are very similar, and one isn’t necessarily better than the others. But doctors may prefer one over the others. And each person responds to drugs differently. If you’re having problems with one AI, tell your doctor. Your body may react better to another one.

To learn more about how these three drugs compare, talk with your doctor or pharmacist.

Is exemestane considered a chemotherapy?

No, exemestane isn’t considered a cancer chemotherapy drug. Instead, it’s a hormone therapy drug.

Hormone therapy slows or stops cancers that depend on hormones to grow. Another name for this kind of treatment is endocrine therapy.

Talk with your doctor to learn more about the different types of cancer treatments.

How does exemestane work? And how long does it take to start working?

Exemestane works by reducing the amount of estrogen your body makes. Certain types of breast tumors need estrogen to grow. (Estrogen is a sex hormone.) They’re called estrogen receptor-positive breast cancers. By lowering the amount of estrogen, exemestane starves these tumors of the estrogen they need to grow.

Exemestane will start lowering estrogen level as soon as you take it. Its maximum effect on estrogen will occur in about 2–3 days. But it can take a few weeks to see a change in your condition. Treatment with exemestane can last for several years.

If you’d like to know more about this, talk with your doctor or pharmacist.

Uses of exemestane

The Food and Drug Administration (FDA) approves prescription drugs such as exemestane for certain conditions. Approved uses for exemestane are described below.

Use for breast cancer

Doctors may prescribe exemestane oral tablet for treating estrogen receptor (ER)-positive breast cancer. It’s used for this purpose in people who’ve gone through menopause (the end of monthly menstrual periods). It’s usually prescribed as a long-term treatment.

With ER-positive breast cancer, the tumor cells have sites that bind to estrogen. (Estrogen is a sex hormone.) When estrogen binds to these sites, it feeds the tumor and helps it grow. Taking exemestane to lower estrogen levels can help slow or stop the growth of these tumors.

Exemestane can treat two kinds of ER-positive breast cancer:

• Early breast cancer. Doctors prescribe this drug after you’ve already taken tamoxifen for 2–3 years. When you switch to exemestane, you’ll complete a total of 5 years of hormone therapy.
• Advanced breast cancer. Doctors prescribe this drug if you have cancer that’s progressing after tamoxifen therapy.

Exemestane can be prescribed together with other breast cancer treatments.

Doctors may not prescribe exemestane oral tablet in certain situations, such as when you haven’t gone through menopause yet.

Interactions and warnings for exemestane

Below, you’ll find information about exemestane’s possible interactions and warnings.

Interactions of exemestane

Certain things may affect how a drug works. These include getting vaccines, consuming alcohol or certain foods, or taking the drug with other medications. This effect is called a drug interaction.

Before you take exemestane, ask your doctor to check for possible interactions. Be sure to tell them about any of the following you take or use:

• prescription or over-the-counter drugs
• vitamins, herbs, or supplements

To learn about drug-condition interactions, see the “Warnings for exemestane” section below.

Warnings for exemestane

Some people should not take exemestane, and others should take it cautiously.

Exemestane could cause harm to people with certain health conditions. This effect is called a drug-condition interaction. Other factors can also affect whether exemestane is a safe option for you.

Ask your doctor about specific warnings for exemestane, and be sure to tell your doctor about your:

• current health, including any allergies to medications
• past health conditions or surgeries

Allergic reaction

Exemestane can cause an allergic reaction in some people. Severe allergic reactions are rare but possible.

If you’ve had an allergic reaction to exemestane or any of its ingredients, your doctor will likely not prescribe exemestane. They can tell you about medications that are safer options for you.

A mild allergic reaction may cause the following symptoms:

• skin rash
• itchiness
• flushing (temporary warmth, redness, or deepening of skin color)

A severe allergic reaction may cause the following symptoms:

• swelling under your skin, usually in your hands, feet, eyelids, or lips
• swelling of your mouth, throat, or tongue, which can cause breathing problems

If you have an allergic reaction to exemestane, call your doctor right away. If you have severe symptoms, call 911 or a local emergency number.

Overdose of exemestane

If you take exemestane by mouth, you should not take more exemestane than your doctor prescribes. For some drugs, doing so may lead to harmful effects or overdose.

If you think you’ve taken too much exemestane, call your doctor or pharmacist right away. Or you could call 800-222-1222 to speak with someone at America’s Poison Centers. You can also use its online resource. If you have concerning symptoms, call 911 or a local emergency number immediately. You can also go to the closest emergency room.

Pregnancy or breastfeeding and exemestane

Information about exemestane and pregnancy and breastfeeding is described below.

Exemestane and pregnancy

Exemestane should not be taken during pregnancy. Keep in mind, doctors prescribe exemestane for estrogen receptor-positive breast cancers in people who’ve gone through menopause. This means you might not be able to become pregnant while taking exemestane.

Exemestane and breastfeeding

Exemestane should not be taken while breastfeeding. Keep in mind, doctors prescribe exemestane for estrogen receptor-positive breast cancers in people who’ve gone through menopause. This means you might not be able to become pregnant while taking exemestane.

What to ask your doctor

Let your doctor know if you have questions about exemestane or would like more details about it.

Here’s a list of some possible questions you may want to ask your doctor:

• Am I at higher risk of side effects from exemestane than other people?
• Does exemestane interact with any of my other medications?
• How should I take exemestane?

Resources

• Exemestane tablets, for oral use. (2022). https://nctr-crs.fda.gov/fdalabel/services/spl/set-ids/f8bd17b4-5289-45bb-8095-de89dc8d39ed/spl-doc
• Food and Drug Administration. (2023). Orange Book: Approved drug products with therapeutic equivalence evaluations. https://www.accessdata.fda.gov/scripts/cder/ob/index.cfm

Disclaimer: Optum Perks has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.